Upstream refers to the exploration and production segment of the oil and gas industry. The upstream sector includes all activities related to searching for potential underground or underwater crude oil and natural gas fields, drilling of exploratory wells, and subsequently operating the wells that recover and bring the crude oil and/or raw natural gas to the surface. This is the first stage in the process of bringing oil and gas to market, preceding the midstream (transportation, storage, and wholesale marketing) and downstream (refining, selling, and distributing) sectors.

The upstream industry is characterized by high risks, high investment capital, long lead times, advanced technology, and being subjected to various geopolitical and environmental challenges. It’s an integral part of the overall value chain in the oil and gas sector and plays a vital role in the global energy supply.

For those looking to explore more about the upstream sector of the energy industry, the following resources can offer additional insights and information:

1. Schlumberger Oilfield Glossary – A comprehensive resource from one of the leading oilfield services companies that includes rich definitions and explanations of terms used in the oil and gas industry, including the upstream sector:
(https://www.glossary.oilfield.slb.com/en/terms/u/upstream)

2. Investopedia Energy Sector Definition – An accessible resource for learning about the different segments of the energy industry, with clear explanations for newcomers to comprehend the basic concepts, including upstream activities:
(https://www.investopedia.com/terms/e/energy_sector.asp)

Please note, web pages and links are subject to change or may become outdated, and while the links provided were active at the time of this response, they may change or become inactive over time.